avowant
/ˌævəˈwɒnt/Definitions
1. adjective
a person who makes a claim or assertion, especially one that is dubious or contentious
“The avowant’s outlandish story drew suspicion from the audience.”
2. noun
a person who avows or claims something, especially something that is questionable
“The avowant’s reputation suffered as a result of their dishonesty.”